In the field of processing chamber deposition, chamber components and surfaces are often modified to facilitate optimum production of work pieces being coated. Deposition processes entail subjecting work piece surfaces to conditions and coatings requiring stringent quality control. Coating thicknesses for many work pieces, such as, for example, semiconductors, are extremely small, often as small as several thousandths of an inch or less. Various plasma coating technologies create byproducts in the deposition chamber that are vented from the chamber atmosphere during or after coating occurs. However, some plasma byproduct remains adhered to the inner surfaces, or walls, of the chamber as well as other chamber components exposed to the inner chamber environment. When byproduct builds up to a predetermined amount, usually based on hours of operation, the production must be brought off line, and the chamber surfaces replaced or cleaned to remove the byproduct build up. If this regular maintenance is not conducted, byproduct may separate from the chamber walls and other exposed components and contaminate the work pieces being coated. This contamination often results in work piece failure or malfunction. As a result, in the coating industry, chamber inner surfaces and chamber components exposed to the inner chamber have modified surfaces designed to increase the adherence of plasma and other coating process byproducts. This enhanced adherence of byproduct to the chamber walls and chamber components increases the processing time achieved between chamber cleanings, which, in turn, increases overall system productivity as the process remains “on line” longer resulting in greater overall product yield. In addition, if the by-product is particularly valuable or otherwise recyclable, by-product adherence to the chamber walls and components is also desired.
Attempts at modifying chamber component surfaces to achieve the proper surface characteristics to effect the desired byproduct adherence are known. However, it has been difficult creating adequate “roughness” on chamber surfaces to increase adhering coating process byproducts thereto.
The substrates of many chamber components are often made from aluminum-alloys or stainless steels. The outer surfaces of these components must then be treated to effect the desired surface features and microscopic contours. Known surface “roughing” techniques include grit blasting, or chemically etching metal surfaces. In addition, coatings have been applied to metal substrate surfaces to create irregular surfaces. These known methods have worked to roughen the metal substrate surfaces. However, all known methods have been somewhat unacceptable in terms of the finite degree of adherence with respect to the amount or volume of byproduct able to be “trapped” by the modified chamber wall surface
In addition, the application of coatings to metal surfaces, introduces additional problems with respect to the nearly permanent adherence of the coating to the metal that must be realized. In other words, coatings applied to chamber wall surfaces that “roughen” the metallic chamber wall surface are not useful if the coatings themselves will eventually delaminate and contribute to the contamination of the work pieces. Known coatings designed to make metallic and non-metallic (e.g. ceramic) chamber walls less smooth must be deposited such that irregularities are presented to the finished surface. However, known methods have not only risked delamination, but have been deposited in a fashion that creates potential gaps that leave the substrate surface coated discontinuously. This results in plasma byproduct being able to react with the substrate surface, or otherwise work to accelerate the delamination of the coating from the chamber wall substrate, further exacerbating the chamber contamination issues and frustrating by-product recycling issues.